Membrane technology has attracted significant research attention due to its many advantages in gas separation. In the present study, Blended membranes were fabricated utilizing sulfonated poly (ether ether ketone) (SPEEK) and poly (etherimide) (PEI) with varying quantities of multi-wall carbon nanotubes (MWCNTs) (up to 2 wt.%). The membranes produced were analyzed using X-ray diffraction (XRD), scanning field emission electron microscopy (FESEM), and Fourier transformed infrared spectroscopy (FTIR). The impact of the SPEEK/PEI composition on membrane selectivity was examined at various feed pressures ranging from 2 to 8 bar. The selectivity and gas permeability values varied between the individual polymers and showed systematic fluctuations with changes in the SPEEK/PEI content in the blends. The incorporation of MWCNTs into the blend resulted in an enhancement of the CO2/ N2 selectivity. The membrane containing the same amount of SPEEK and PEI, along with 1 wt.% of MWCNTs (designated as SP55M1), exhibited an approximately 22% increase in the selectivity of CO2/N2 compared to the pristine membrane. Manuscript profile